Lattice constant of orthorhomic perovskite solids

Thermoelectric properties of Sr–Ir–O compounds prepared by spark plasma sintering

“…It is characterized by a six-layered hexagonal (6H) structure consisting of close-packed Sr-O layers stacked perpendicular to the c axis in the sequence hcchcc, where h and c refer to hexagonal and cubic stacking. Kumar and Verma theoretically investigated the crystal structure of SrIrO 3 , and reported that these calculated lattice parameters were consistent with their experimental values with a 0.6-1.1% error [2]. Sr 3 Ir 2 O 7 belongs to the tetragonal, body-centered space group of I4/mmm, and consists of bilayers of corner-shared IrO 6 octahedra interleaved with Sr-O layers, similar to that of Sr 3 Ru 2 O 7 .…”

The prediction of lattice constants in orthorhombic perovskites

“…[25]. Similarly, correcting the errors in the ionic radius of Ru 4+ VI (r = 0.62 Å not 0.68 Å) [26] as well as the c parameter of DyCrO 3 (c = 5.520 Å not 5.2 Å) [27] improves the fit overall.…”

“…[25], which contains the structural details of 152 orthorhombic oxide perovskites, | ā o |, | b o |, | c o |, and |error| are equal to 0.915%, 4.185%, 3.181%, and 8.281, respectively; however, simply modifying the results from Ref. [19] as above one obtains better overall results: 1.880%, 2.576%, 1.087%, and 5.543.…”

“…Similarly, correcting the errors in the ionic radius of Ru 4+ VI (r = 0.62 Å not 0.68 Å) [26] as well as the c parameter of DyCrO 3 (c = 5.520 Å not 5.2 Å) [27] improves the fit overall. Finally, there are several inconsistencies in the table compiled by Kumar and Verma [25]. While the lattice constants of most compounds are listed assuming a Pbnm model, several are listed in Pnam (CaVO 3 , SrRuO 3 , SrCeO 3 , LaCrO 3 , LaGaO 3 , LaTiO 3 , and SmAlO 3 ).…”

“…Consequently, structural prediction based on easily obtainable parameters for compounds with novel compositions remains an important problem in the area of solid-state chemistry. Kumar and Verma [25] recently reported equations describing the relationship between composition and lattice constants based on a combination of ionic charge and radii. Unfortunately, their list of orthorhombic perovskites contains only oxides, so it is unclear if their approach would work for the more generic case of ABX 3 ; and the errors reported in lattice constants were up to 10% in some cases.…”